Evening star. [volume] (Washington, D.C.) 1854-1972, 1887-03-05

SHADE TREES AND THEIR FOES.
How 70 Deal with the Pests thas De:
strOy the Foliage.
ONE SIMPLE PREVENTIVE REMEDY FOR Au-wHITR-
WASH TREE BOXES AND sPARRows-rHH PRUNING
OF TREEs-FURTHER REMARKS BY PROF. Riley.
In an article published in TEE STAR Of Tuesday
Prof. c. V. Riley gave an account OF the Elm Leaf
Beetle, the Bag Worm, the White Marked Tussock
Moth and the web Worm, the four insects indicted
for devastating shade trees OF the city with some
suggestions as to preventive measures that can be
taken during the winter time. Prof. Riley writes
to TIE STAR as follows in continuation OF his re-
marks published Tuesday:
ONE SIMPLE PREVENTIVE REMEDY FOR ALI.
It so happens, fortunately, that there is one
thoroughly simple, cheap and efficaciOus remedy
applicable to all four OF these tree depredatorS
From the natural history facts already given It is
clear that they all begin their work very much at
the same season or as soon as the leaves are fairly
developed, and arSenical mixtures properly
sprayed on the trees about the middle OF May and
repeated once or twice at intervals Of fortnight
e % 1e a. All Vim Th aR @ s
small expense and will prove the salvation Of the
trees. An apparatus can be readily constructed,
such as has been used On the grounds OF the De-
partment Of Agriculture, on sufficiently Large
scale TO economic time and labor. 1t should con-
sist of a water tank mounted on a cart and
furnished with strong force pump operated
by one man and furnished with two sets OF rubber
tubing of sufficient length "a hose reel can be con-
by bamboo extension pole with a cyclone nozzle
at tip. With such an apparatus as this three men
could drive along the streets and thoroughly spray
advisable, four Independent tubes and four men
to work them could be employed with sufficiently
powerful pump, and thus expedite the work. The
details OF the different more important devices
connected with this tank-cart will be found in my
annual report as entomologist to the Department
of Agriculture for 1883. The bamboo sextension
pole" is used simply TO stiffen the rubber hose and
to enable the operator to elevate the spraying
nozzle into the center of the tree and spray to
much greater height. The same result can be &C.
compl1shed by means OF brass rod, In sections,
and this has the advantage OF superior strength,
ana wiz consequently carry heavier nozzle or
The "Cyclone' or Eddy chamber" nozzle has
been described and figured in several OF my re-
ports, and is better suited for work OF this kind
than any yet in use. 1t is small simple, cheap,
Will not clog and gives an admirable spray. A COM
bination nozzle may be made of several OF these,
which viii be readily supported by the Sec1on-rOd
and will throw more prOfuse spray.
The arsen1cal compound known as London pur-
and containing from 40 to So per cent Of arsenicus
acids, perhaps, preferable to white arsenic or
Paris green in that it is not so liable to burn the
leaves while its color enables to readily d1stin-
guish poisoned from non- poisoned trees Moreover
1t Is very cheap. From to OF pound Of this sub
stance should be used to barrel Of water and with
quarts OF cheap or damaged -four which Will serve
both to render the mixture adhesive to the leaves
and also to lessen the tendency OF the poison to
burn the leaves. Three-QuarterS of q pound to
the barrel may prove too strong mixture for deli
cate and susceptible young trees and it viii be
from y to q pound to the barrel. Paris green viii
require somewhat heavier dOse-say from Il to
pound per barrel OF water.
A number of other means have been tried and
are more or less ehectual in destroying these de-
foliatOrs. Such are the application OF various
other insecticides, particularly an emulsion OF
milk and kerosene, the burning of the webs On
case OF the web-worm) by thrusting a lighted
torch made OF various patterns into the webs but
after full trial nothing has been found more sat
iSfactOry than the arsentcal mixture here recon-
mended. They have the advantage over all other
means that they kill directly the worms begin
feeding, and at the same time have preventive
influence. Properly sprayed on the under side OF
the leaves SO as to adhere, they are not easily
washed on, and they not only kill without injury
to the tree all the worms at the time upon such
tree, but all those which may hatch upon such
| tree for number Of days and even weeks subse-
Quently.
am satisfied that with two or three special
tanks, such as have built at the Department OF
Agriculture, and gang OF three men to each, the
trees OF the city could be easily protected at a
nominal cost beyond labor, and that two spray.
ingS, one about the middle OF May, and one the
first week in June, will enectually prevent the
repetition OF any such nuisance that we suffered
from last summer. Each gang Of three men could
properly protect in the neighbOrhOOd OF from 800
TO 500 medium-sized trees per day, and in ordi-
would only be necessary to poison such trees as
are preferred by the insect.
wHITRwAsHING THE TRUNKS.
No question has more often been asked me by
those interested and few have been more discussed
than the effect Of embarrassing the trees upon the
injuries OF the web worm. There is a popular but
totally unjustif1ed sentiment that such white
washing in some way or other protects the trees.
will not discuss the esthec side of this question;
for, however much such whttened trunks may Of
fend the eye OF the true lover OF beauty in nature
tastes differ, and some persons are pleased with
the artificial and ridiculous Only one of the in
Sects mentioned can lie in any way lesSened by this
practice and that is the species that Washington
ianS are just now least concerned with, viz, the
ogya NH, Il Is very whether the white
son to believe that the friction Of the brush
and the disengag1ng Of many OF the cocoons
will cause the destruction OF a certain
number Of these cocOOns are never reached by
such embarrassing, because they are upon the
by the practice the alternating chrySaldes and
cOcOons are not found upon the trunks As against
these negative results OF wh1tewashing, however,
directly, because great many of the enemies Of
the defOltatorS are destroyed by whitewashing
This is particularly the case with the egg masses
cate cOcoons OF parasites. Whitew ASKING covers
multitude Of sins and even when it is employed
| we bore into the trunks, but which we are not
considering there is no reason why the lime should
not be cOOred so as 10 keep the appearance OF the
| trees somewhat IL harmony with nature.
INFLUENCE OF TREE Boxes
The tendency which our horses and other ami.
mails have when opportunity is offered to gnaw
and injure the trunk, and the propensities OF mis-
chievOuS boys in all our large cities to cut the
| same render tree boxes necessary, especially
while the trees are young. But the clumsy wooden
| tree boxes in this city are not only an eyeSOre
but positive injury, to the trees after these have
once attained sufficient growth to be firmly rooted
! The boxes cause a great deal OF chaflng OF the
| branches and the bandageS connected with then
great deal OF binding OF the young trees but they
are particularly pern1cOuS as harbOrS for hfberna
| shelter afforded by the wooden tree boxes Is
| in my judgment, the prime reason why the web
worm has become such great nuisance in Wash.
| ington. They should either be discarded entirely
| after the trees have attained trunk diameter o.
four inches and heavy penalties enacted for hitch
ing horses or for in any way cutting or defacine
| the trunk Or what would perhaps be safer anS
| certainly very much less Objectionable, they
| should be replaced rs soon as possible by round
iron ones Ike those now in use on 18th street. be
| tween New York avenue and K street. These vii
afford less shelter for cOcOOnS and in every Way
| less Objectionable.
| BIRDS: THE ENGLISH SPARROW.
All four Of these insects have certain fmmu
nifty from the attacks of birds No. 1, by virtue O
an offensive odor; No. 2, by the protection of It.
bag: Nos 3 and 4, by the protection afforded b,
the hairs Of the caterpilars which are also mixed
| into their cocoons. 4 few native birds are known
| to occasionally feed upon Nos. 3 and 4 but the
| English sparrow, to which, being alphabetically /
city bird we should look for help has never beer